The present application claims priority under 35 U.S.C. xc2xa7119 of German Patent Application No. 199 29 927.7, filed on Jun. 29, 1999, the disclosure of which is expressly incorporated by reference herein in its entirety.
1. Field of the Invention
The invention relates to a device for separating and transferring a leader strip to be threaded into a machine for producing and/or treating a material web, in particular a paper or cardboard web, having a separating device and a transfer device that is used to transfer the leader strip into a subsequent device of the machine after a successful separation.
2. Discussion of Background Information
Such a device can be used, for example, to thread a paper web into a paper machine. As a rule, it is impossible to thread the entire width of the material web because of the large web widths. Therefore, a leader strip, which is threaded into the paper machine and subsequently pulls the entire width of the paper web after it, is cut from the web. The threading process occurs during startup of the paper machine or after a web tear. The device mentioned can be used practically at any given point in the paper machine, e.g., at the end of the dryer section or between a smoothing machine and a winding device.
In a device of the type mentioned at the outset that is known from DE 44 09 660 A1, the leader strip is separated in that a guide panel mounted in a pivoted manner on a doctor bar is pivoted with its free end along a separating edge past a further guide panel. Thus, the strip separation occurs between two guide panels, at least one of which must be mounted in a pivoted manner.
In a further separating and transferring device known from DE 39 24 897 A1, the leader strip is separated in a channel formed between two guide panels by means of a water jet cutter. At least one of the two guide panels is pivotable here as well.
In a separating and transferring device described in U.S. Pat. No. 4,923,567, the leader strip is separated by means of an air or water jet cutter. The leader strip is subsequently deflected to a guide panel arranged before the separating device in the strip travel direction which is tangentially loaded by a jet of air in order to continue to guide the web along this panel.
In a separating device known from EP 0 554 339 B1, the strip separation is performed by means of two knives rotating in opposite directions. The leader strip is guided to these rotating knives by means of a pivotable guide panel. The separating device that includes the rotating knives can be pivotable into the region of a vacuum belt, which further transports the leader strip after the separation process. After each separation process, the separating device is again pivoted away from the vacuum belt.
The object of the invention is to create a device of the type mentioned at the outset which can not only be produced in a cost-effective manner, but also has a relatively compact construction and, in particular, can be easily integrated, for example, into a pre-existing dryer section. Furthermore, it should be useable in new and in renovated plants in the simplest way possible.
This object is attained according to the invention in that the separating device and the transfer device are preferably attached to a common plate upon which the leader strip is guided before separation and can be pre-stressed before the separation process and in that the transfer device is arranged before the separating device in the strip travel direction (L).
This design results in a construction for the entire device that is extremely simple and compact overall. Not only can the device be produced in a cost-effective manner, it can also be integrated in a trouble-free manner, in particular into a preexisting drying section. With the solution according to the invention, a greater flexibility is also achieved in view of the possible applications. Thus, the device according to the invention can be used in a trouble-free manner in renovated as well as new installations.
The plate is preferably firmly attachable to a doctor bar. Thus, pivoting the plate is no longer necessary.
In a preferred practical embodiment of the device according to the invention, the transfer device is formed by an air transfer device.
In order to stabilize the leader strip before the separation process, the side of the plate facing the leader strip can be at least essentially tangentially loaded with an appropriate jet of pressurized air.
In a suitable practical embodiment, at least one air guide panel is provided following the separating device on the side of the plate facing the leader strip for the purpose of pre-stressing the leader strip in the strip travel direction. The air guide panel is preferably inclined relative to the surface of the plate facing the leader strip in such a way that the leader strip is lifted from this plate surface and appropriately guided through the separating region of the separating device. This ensures that the leader strip can subsequently be separated in a reliable manner. More suitably, at least two guide panels are provided that are arranged one behind the other in the strip travel direction.
In a suitable practical embodiment, the transfer device provided as an air transfer device has several air nozzles. These nozzles can be adjustable and appropriately moveable.
It is also advantageous for the air transfer device to have an air blast pipe that includes at least one row of air nozzles extending parallel to the pipe axis. At least some of the air nozzles can be adjustable or moveable relative to the air blast pipe. Alternately or additionally, the air blast pipe can be adjustable and rotatable around its axis.
The jet of pressurized air that is necessary for stabilizing and/or pre-stressing the leader strip can advantageously be produced by means of adjustable air nozzles of the air transfer device, where the leader strip should preferably be pre-stressed. In principle, however, it is also conceivable to provide separate air nozzles for this kind of stabilization and pre-stressing.
In particular, the separating device can be designed for performing a scissor cut and/or a parallel cut.
In a suitable practical embodiment of the device according to the invention, the separating device has at least two cutting elements, particularly knife-like cutting elements, which are attached in an adjustable manner to two frame parts which are moveable relative to one another.
In a preferred practical embodiment, the two frame parts are pivotable relative to one another.
In certain cases, it can be advantageous for the separating elements of the separating device to be at least partially formed by smooth cutting elements. In principle, however, these separating elements can also be formed, at least in part, by perforated and/or toothed cutting elements.
The present invention is directed to an apparatus for separating and transferring a leader strip to be threaded into a machine for at least one of producing and treating a material web. The apparatus includes a separating device positioned to perform a separation process, a transfer device positioned to transfer the leader strip to a subsequent device of the machine after the separation process, and a common plate positioned to guide the transfer strip prior to the separation process. The transfer device is positioned upstream, relative to a strip travel direction, from the separating device.
According to a facet of the instant invention, the separating device and the transfer device can be coupled to the common plate. Further, at least one device can be arranged to pre-stress the leader strip prior to the separation process. The separation process can include separating the leader strip to form an end to be transferred to the subsequent device, and the material web can be one of a paper and a cardboard web. Moreover, the pre-stress device can be positioned downstream of the transfer device. The pre-stress device can also be positioned downstream of the separating device.
In accordance with a feature of the invention, a doctor bar may be provided, and the common plate can be firmly attached to a doctor bar.
In accordance with another feature of the present invention, the transfer device can include an air transfer device.
The transfer device may include at least one positionably adjustable nozzle. Prior to the separation process, the at least one nozzle can be positionable to direct a jet of air at least essentially tangentially to the common plate, thereby stabilizing the leader strip for separation.
Further, the transfer device may include at least one positionably adjustable nozzle. Prior to the separation process, the at least one nozzle may be positionable to direct a jet of air substantially along a leader strip carrying surface of the common plate, thereby stabilizing the leader strip for separation.
At least one air guide panel may be positioned downstream from the separating device and on a leader strip facing surface of the common plate. The at least one air guide panel can be arranged to pre-stress the leader strip prior to the separation process. The at least one air guide panel can be arranged to lift the leader strip off of the leader strip facing surface of the common plate. In this manner, the leader strip may be guided through a separating region of the separating device. Further, the at least one air guide panel can include at least two air guide panels positioned one behind the other in the strip travel direction.
In accordance with a further feature of the instant invention, the transfer device can include an air transfer device including several air nozzles. The air nozzles may be adjustable and moveable. The transfer device may include an air blast pipe with at least one row of air nozzles extending parallel to a tube axis. At least a portion of the air nozzles can be adjustable and moveable relative to the air blast pipe. The air blast pipe can also be adjustable and rotatable around the tube axis.
According to still another feature of the invention, the transfer device can include an air transfer device with positionably adjustable air nozzles. The adjustable air nozzles may be positionably adjustable to direct a jet of blown to at least one of stabilize and pre-stress the leader strip.
According to a still further feature of the present invention, the separating device may be arranged to produce at least one of a scissors cut and a parallel cut.
Moreover, the separating device can include at least two separating elements which are movable relative to each other. The at least two separating elements may be knife-like elements. Also, the at least two separating elements can be adjustably mounted on two frame parts that are movable relative to one another, and the two frame parts may be pivotably coupled to one another. The separating elements can be adjustably attached to the frame parts by set screws.
According to another facet of the present invention, the separating device can include separating elements which are at least partially constructed of smooth cutting elements.
In accordance with still another facet of the instant invention, the separating device can include separating elements which are at least partially constructed of at least one of perforated and toothed cutting elements.
The transfer device may include at least one positionably adjustable nozzle. Further, prior to the separation process, the at least one nozzle can be positionable to direct a jet of air to create a low pressure between the common plate and the leader strip, whereby the leader strip is guided against the common plate.
Further, a doctor can be located adjacent an element of the machine and positioned to remove the leader strip from the element. A surface of the doctor can face the leader strip is arranged to be substantially coplanar with the common plate.
The present invention is directed to a process for separating and transferring a leader strip to be threaded into a machine for at least one of producing and treating a material web. The process includes guiding a transfer strip over a common plate, separating the transfer strip with a separating device, and transferring the transfer strip to a subsequent device of the machine after the separating with a transfer device. The transfer device is positioned upstream, relative to a strip travel direction, from the separating device.
In accordance with a feature of the invention, the separating device and the transfer device can be coupled to the common plate. Further, the process can include pre-stressing the leader strip prior to separating. The separating can occur downstream of the transfer device. Still further, the process can include pre-stressing the leader strip prior to separating, and the separating may occur downstream of the separating device.
According to another feature of the invention, the process can also include directing a jet of air at least tangentially to the common plate, thereby stabilizing the leader strip for separation.
In accordance with still another feature of the present invention, the process can also include directing a jet of air substantially along a leader strip carrying surface of the common plate, thereby stabilizing the leader strip for separation.
Further, the process can include pre-stressing the leader strip prior to separating by directing an air jet obliquely to the strip travel direction.
According to yet another feature of the present invention, the process can include directing an air jet to press the leader strip against the common plate via the Coanda effect.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.